1. Field of the Invention
The invention relates to a light emitting diode backlight unit, and more particularly, to an arrangement method of light emitting diodes within the light emitting diode backlight unit.
2. Description of the Prior Art
Liquid crystal displays are commonly utilized in various electronic products including cell phones, PDAs, and notebook computers. As the market demand for large-scale display panels continues to increase, liquid crystal displays having advantages such as small size and light weight have become widely popular. Due to the fact that the liquid crystal display itself does not illuminate, a backlight unit has to be installed under the liquid crystal display to provide an area light source for the liquid crystal display.
Backlight units are commonly divided into two major categories: side-emitting type and direct type. Additionally, the area light source provided for the liquid crystal display is divided into two types: one being arranging a plurality of code cathode fluorescent lamps (CCFL) of external electrode fluorescent lamps in a parallel manner, and the other one being arranging a plurality of dot light source, such as a plurality of light emitting diodes corresponding to a matrix. Since light emitting diodes have the advantage of high color saturation, being mercury-free, having long life expectancy, a low temperature, and have the ability to adjust color temperature through a driving current, they have been commonly utilized in backlight units.
Please refer to FIG. 1. FIG. 1 is a perspective diagram illustrating an arrangement of light emitting diodes of a light emitting diode backlight unit 10 according to the prior art. As shown in FIG. 1, the light emitting diode backlight unit 10 includes a plurality of light emitting diode modules 12. Each of the light emitting diode modules 12 includes three light emitting diodes 14 and each of the three being a different color, such as red light emitting diodes, blue light emitting diodes, and green light emitting diodes. Preferably, the light emitting diodes 14 of each light emitting diode module 12 are arranged in a manner of a straight line, and all of the light emitting diodes 14 of the adjacent light emitting diode modules 12 are arranged according to a same direction and the colors of the light emitting diodes 14 of the light emitting diode modules 12 are arranged in a same order.
The conventional arrangement described above however, often results in serious problems. For instance, if the light emitting diodes 14 of the light emitting diode module 12 in the first column and first row are arranged in an order of red, green, and blue, the light emitting diodes 14 of the light emitting diode module 12 in the adjacent first column and second row are also arranged in the same order. Since the color arrangement of the light emitting diodes 14 of the adjacent upper and lower light emitting diode modules 12 is opposite to each other, an uneven color distribution will result in the intersecting region of the two adjacent light emitting diode modules 12, as shown in the figure.
Please refer to FIG. 2. FIG. 2 is a perspective diagram illustrating an arrangement of light emitting diodes of a light emitting diode backlight unit 20 according to the prior art. In contrast to the arrangement shown in FIG. 1, the arrangement in this example is commonly found in the side region of the backlight unit. As shown in FIG. 2, the light emitting diode backlight unit 20 includes a plurality of light emitting diode modules 22. Each of the light emitting diode modules 22 includes three light emitting diodes 24 and each of the three being a different color, such as red light emitting diodes, blue light emitting diodes, and green light emitting diodes.
Similar to the problems described previously, since the light emitting diodes 24 of the adjacent light emitting diode modules 22 arranged horizontally in the first row are arranged in a same manner and same color order, and the light emitting diodes 24 of the adjacent light emitting diode modules 26 arranged vertically in the first column are arranged in a same manner and color order, an uneven color distribution will result in the central region of the backlight unit, as indicated by the circle with slanted lines illustrated in FIG. 2.